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A floating-point number is a number with zero or more digits behind the decimal separator. Examples are -2.4, 0.1, 3.14, 5., 16.984025 and 1024.0.

Different floating-point types can store different numbers of digits after the digit separator - this is referred to as its precision.

Go has two floating-point types:

• float32: 32 bits (~6-9 digits precision).
• float64: 64 bits (~15-17 digits precision). This is the default floating-point type.

As can be seen, both types can store a different number of digits. This means that trying to store PI in a float32 will only store the first 6 to 9 digits (with the last digit being rounded).

By default, Go will use float64 for floating-point numbers, unless the floating-point number is:

1. assigned to a variable with type float32, or
2. returned from a function with return type float32, or
3. passed as an argument to the float32() function.

The math package contains many helpful mathematical functions.

Always be careful when checking the values of floating-point types for equality, as values that can appear to represent the same value could actually be different.

You can find a short introduction to floating-point numbers at 0.30000000000000004.com. The Float Toy page has a nice, graphical explanation how a floating-point numbers’ bits are converted to an actual floating-point value.

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Originally from Exercism go concepts